U.S. Pat. No. 4,643,876, incorporated herein by reference, discloses a sterilization system in which an agent such as hydrogen peroxide is introduced into a evacuated sterilizing chamber where it is vaporized and allowed to disperse onto the items to be sterilized. After a desired period of time, electrical energy is applied to the chamber to ionize the gas and form a plasma field at a power level sufficient to achieve sterilization.
This system has been successfully commercialized as the STERRAD® Sterilization System and is available from Advance Sterilization Products, Division of Ethicon Endo-Surgery, Inc., Irvine, Calif. The system is used in hospitals and other environments where it is operated repeatedly throughout the day by personnel having a widely varying range of understanding of the apparatus. To ensure simple and automatic operation with adequate safeguards with respect to human error, the system employs an automated delivery system for delivering the liquid sterilant to the sterilization chamber. Measured portions of the sterilant, in this case hydrogen peroxide but many other sterilizing agents could be substituted therefor, are provided in rupturable cells within a rigid cassette housing. A transport system maneuvers the cassette within the STERRAD® sterilizer and releases the given quantity of hydrogen peroxide into the sterilization chamber automatically. One form of cassette and operation of the deliver system are more fully described in the Williams et al. U.S. Pat. No. 4,817,800 issued Apr. 4, 1989; U.S. Pat. No. 4,913,196 issued Apr. 3, 1990; U.S. Pat. No. 4,938,262 issued Jul. 3, 1990; and U.S. Pat. No. 4,941,518 issued Jul. 17, 1990, all of which are incorporated herein by reference.
An improved cassette and delivery system is shown in the Williams et al. U.S. Pat. No. 5,882,611 directed to a sleeve which retains and protects the cassette and U.S. Pat. No. 5,877,716 directed to an indicia system on a cassette sleeve. Each of these patents are incorporated herein by reference. The '611 patent describes a sleeve having an inner layer of corrugated cardboard and an outer layer of pressboard, producing a sleeve of considerable thickness.
The present cassette and sleeve employ a single layer sleeve which eases manufacturing and reduces the expense of the sleeve and employs a pair of folded tabs to accommodate both the present type of cassette and sleeve and that shown in the '611 patent in the same machine by providing that the important external dimensions of the cassette and sleeve can be the same for each system even though the present system employs a sleeve having a different thickness.